Google’s driverless cars have driven more than 1.6 million miles in four different cities and over seven years, and yet have never resorted to honking their horn in anger.

That could be about to change. Google revealed in its latest monthly report on driverless cars that it is teaching its robot vehicles to beep at other drivers, although it promises to “be polite, considerate, and only honk when it makes driving safer for everyone”.

Google says the car horn – ubiquitous in US traffic jams – will be activated only when its cars need to alert others to its presence, such as when they are backing out of a driveway or swerving into a lane, rather than to scold rude drivers.